Effect of Si content on microstructures, tensile properties, and creep properties in a cast Mg–6Al-0.4Mn–2Ca (wt.%) alloy

Effect of Si content on microstructures, tensile properties, and creep properties in a gravity-cast Mg–6Al-0.4Mn–2Ca (wt.%, AMX6042) alloy has been investigated. High content of Si addition increases the ductility of the AMX6042 alloy without large loss of strengths; however, addition of Si over 0.6 wt.% decreases fraction of (Mg,Al)2Ca phases significantly. Moreover, such high content of Si promotes formation of Mg17Al12 phases, leading to poor creep properties. Although addition of Si tends to decrease fraction of (Mg,Al)2Ca phases and promote formation of Mg17Al12 phases, good creep properties could be kept up to 0.47 wt.% Si addition.